1. Field of the Invention
This invention relates in general to archery sighting devices, and in particular, to sighting devices which utilize adjustable or mobile crosshairs to aim at a target.
2. Description of Related Art
For years, archers have struggled with unsatisfactory sighting devices which, although an improvement over instinct shooting, did not fulfill the modern archer's needs. These devices were imprecise, inaccurate, and difficult to adjust under changing shooting conditions. With the advent of powerful compound bows, the accuracy of available sighting devices has decreased further due to the increase in the speed of the arrow. If more force is applied behind an arrow, the arrow travels faster, and a lower trajectory is achieved. Thus, the archer must space the pins much closer together when using such a bow. If the design of a sighting device makes this impossible, the device is useless to a compound bow shooter. In addition, if an archer wishes to change the type of bow or arrow used or compensate for other encountered variables, he needs a method whereby he can set and reset his sight with a minimum of time and effort. This same sight, while being easy to adjust and reset, must also be durable and reliable enough that the settings will not easily shift over time or be easily damaged in the field.
Several inventors have offered devices intended to alleviate one or more of the above-enumerated obstacles, but none of the prior art inventions has comprehensively met the modern archer's needs. The prior art sights which I have found to be closest in concept to the present invention will be referenced in the following discussion:
U.S. Pat. No. 3,136,063 issued to Herve A. Stebbins on Jun. 9, 1964 was the first to allow for a multiplicity of crosshair sights, each of which could be adjusted independently of the others. The sight was limited in that the shooter was required to effectively dismantle the device to change a pin position. Once the plates had been removed, all of the pins were exposed, and thus, were vulnerable to change. In addition, the design made adjustment awkward and clumsy and precluded a closely-spaced positioning of range pins.
The next patent of interest also belonged to Herve A. Stebbins, namely U.S. Pat. No. 3,670,422, issued on Jun. 20, 1972. This device alleviated the need for disassembly and provided a finer adjustment. However, these improvements presented other obstacles. For example, the removal or insertion of pins was difficult and complex. In addition, the sight pins were tedious to adjust, requiring a special tool to be carried at all times. The pins were held in place by set screws which could easily work their way loose, allowing the pins to gradually move downward. Most importantly, the size of the set screws did not allow the pins to be placed closely together as is necessary with the high-speed modern bows.
Another representative patent is illustrated in U.S. Pat. No. 4,136,462 which was issued to Kenneth D. Topel on Jan. 30, 1979. Although this invention also allowed a fine adjustment, it required a separate, bulky mounting mechanism for each horizontal wire, limiting the proximity in which two wires could be placed. The mounting mechanisms were composed of a screw apparatus which could slip and allow the crosshairs to move. These crosshairs were not supported on one end, and this added to their instability.
The most recent crosshair sight is described in the patent issued to Marlow W. Larson on Sep. 24, 1991 and designated U.S. Pat. No. 5,050,576. This device allows for a fine adjustment and a closer placement of sight pins. However, this sight as well uses screws to hold the vertical pin positions. It is well known that screws gradually loosen, and this would permit the pins to move. The pins are secured at one end only, leaving the opposite end free to snag brush during rigorous hunting conditions.
In addition to the aforementioned problems, all of the prior art sights are difficult to resight if a shooter should change the type of bow or arrow used or otherwise need to vary the pin positions. Any time such a change is made, each and every pin must be individually reset. No change in pin position can be made, not even to a previously used position, without using numerous test shots. To be truly effective under modern shooting conditions, a sight must provide for a solution to this and a multitude of other problems.